The present invention relates to a portable device for remotely controlling a device of a vehicle.
Due to the progress in information communication technology and the widespread use of communication devices, remote control is performed in various fields with portable devices. A remote controller used to perform such remote control includes a portable device, which is operated by a user (owner), and a transceiver, which is installed in an external device. For example, the remote control of a household appliance using a cellular phone and the remote control of a vehicle using an electronic key are known in the art.
FIG. 1 shows an example of a portable device 50 described in Japanese Laid-Open Patent Publication No. 2002-339605 used for remotely controlling a vehicle. The portable device includes a case 51, which is made of a synthetic resin and which accommodates a battery 52, a mechanical key 53 used during emergencies, a plurality of electronic components 54, and a circuit board 55. When the battery 52 is drained, a user uses the mechanical key 53 to lock or unlock the door of the vehicle and to start the engine. Referring to FIG. 2, the outer surface of the case 51 includes an opening 56, through which the mechanical key 53 is removed, and a lid 57, which enables the battery 52 to be changed. The lid 57 is normally a slide-type lid such as the one shown in FIG. 2 or a fixed lid fastened by a screw. To improve the portability and convenience, there is a strong demand for a thinner portable device 50.
However, a thinner portable device 50 would decrease the strength of the case 51 and the circuit board 55 that form the portable device 50. For example, when a user carries the portable device 50 in a garment pocket or a wallet, the application of external force to the portable device 50 may deform or damage the case 51 and the circuit board 55. In addition, deformation of the case 51 may cause the lid 57 to fall off from the outer surface of the case 51. This would affect the water resistance of the portable device 50.